Shuttles and Rug

I haven't worked with stick shuttles very much over the years. As a matter of fact, I had to buy four just to do this rug project. I wasn't sure what size to get, so I got  medium ones. At least 18" looked like a medium one to me.

So far, I have found out that I needed to load two different shuttles with the same yarn so that when I came to the end of a repeat I didn't have to stop, load the shuttle, then try to remember where I was.

Here is showing the shuttles and it also shows that I am using three strands of wool.

I am at the 9 inch mark. My loom is slipping and I am having to "dork" with it to keep the tension tight. I am used to this on this loom. I suspect it's the operator! Or bad maintenance on the operators part!! Slows me down, but that could be a good thing!!!